diastole

1. Physiology. The normal rhythmically occurring relaxation and dilatation of the heart chambers, especially the ventricles, during which they fill with blood.
2. The lengthening of a normally short syllable in Greek and Latin verse.

[Greek diastolē, dilation, separation, from diastellein, to expand : dia-, apart; see dia- + stellein, to place, send.]

1. the rhythmic period of relaxation and dilation of a chamber of the heart during which it fills with blood. n 2. the period after the contraction of the heart muscle, during which the aorta releases the potential energy stored in its elastic tissue. The energy is converted into kinetic energy and sustains the pressure necessary for steady flow of blood in the vessels. The pressure measured at this period is the lowest attained during the cardiac pumping cycle and is called the diastolic pressure. The normal pressure in the adult is approximately 120/80 mm Hg (systolic/diastolic) and increases with age from 128/85 at 45 years of age to 135/89 at 60 years of age.

Resting phase of the cardiac cycle when all parts of the heart are relaxed. It occurs immediately after systole and lasts about 0.5 s, assuming one complete cardiac cycle takes 0.8 s.

The phase of the cardiac cycle in which the heart relaxes between contractions; specifically, the period when the two ventricles are dilated by the blood flowing into them. See also blood pressure and heart.